If you started university after 1998, then your student loan will definitely not appear on your credit report.
If it's not on your report, then it's not counted towards your debt to income ratio or credit utilisation ratio within Credit Club.
But, in the real world, if you are repaying a student loan, it is going to impact on the amount of disposable income you have, so lenders will take it into account when deciding whether to lend to you.
If you took out your student loan before 1998, then the Government has sold these loans to three debt collection agencies. You can defer payments if you earn less than £29,126, but without an official deferral, if you don't pay, then these agencies can mark you as in arrears on your credit report(s).